Interview Questions

General Qs

- Describe the Linux boot process. 
*A:*  BIOS, MBR, bootloader, kernel, initialization, and runlevel

- What is DNS? And what does it do in a network? 
*A:* DNS stands for Domain Name System, and it is responsible for handling name resolutions back to IP addresses

- What happens when you `curl google.com`?
*A:* Open ended question, can refer to how DNS works, what the app server will do, the TCP connection, etc.

- How do you get exit status code of your last bash command? 
*A:* Run `echo $?`

- How do you check the filesystem usage on a system? Such as the percent of your mount used.
*A:* `df`

- Scenario: You ssh onto a remote box, and try to touch a file in your home directory, but an error is thrown when touching the file, you take a look at df and it reveals that you still have available space on the filesystem - what could be the issue?
*A:* You've run out of inodes on your system. 

- What are inodes?
*A:* An 'inode' is a 'data-structure', which is used for file identification on Linux. Each file on an Unix System has a separate ‘inode’ and an ‘Unique’ inode Number.

# Open ended questions

- What are some examples of how you might scale a write/read-heavy application? Why? 

- Tell me about the worst-run/best-run outage you’ve been a part of. What made it bad/well-run?

- How do you handle interruptions?
*NOTE* While it’s going to be your job to stop interruptions, how you deal with them now is important for getting an idea of if you know how to fix them quickly and if you know how to make devs and ops work together.

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